RA Capital discloses 7% Helix Acquisition III (HLXC) stake via 13G

Rhea-AI Filing Summary

Helix Acquisition Corp. III received a Schedule 13G reporting that RA Capital Healthcare Fund, L.P. directly holds 1,250,000 Class A ordinary shares, equal to 7.0% of the class. This percentage is based on 17,747,500 Class A ordinary shares outstanding as of January 26, 2026.

RA Capital Management, L.P., and its managers Peter Kolchinsky and Rajeev Shah may be deemed beneficial owners for Section 13(d) purposes through their roles over the fund, but each disclaims beneficial ownership beyond reporting obligations. The filing is made on a passive basis, certifying the shares are not held to change or influence control of Helix Acquisition Corp. III.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Helix Acquisition Corp. III

(Name of Issuer)

Class A Ordinary Shares, par value $0.0001 per share

(Title of Class of Securities)

G4444S107

(CUSIP Number)

01/26/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP No. G4444S107

1

Names of Reporting Persons

RA Capital Management, L.P.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,250,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,250,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,250,000.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

7.0 %

12

Type of Reporting Person (See Instructions)

IA, PN

SCHEDULE 13G

CUSIP No. G4444S107

1

Names of Reporting Persons

Peter Kolchinsky

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,250,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,250,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,250,000.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

7.0 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

CUSIP No. G4444S107

1

Names of Reporting Persons

Rajeev Shah

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,250,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,250,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,250,000.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

7.0 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

CUSIP No. G4444S107

1

Names of Reporting Persons

RA Capital Healthcare Fund, L.P.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,250,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,250,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,250,000.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

7.0 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Helix Acquisition Corp. III
(b)	Address of issuer's principal executive offices: Cormorant Asset Management, LP, 200 Clarendon Street, 52nd Floor, Boston, MA, 02116.
Item 2.
(a)	Name of person filing: The names of the persons filing this report (collectively, the "Reporting Persons") are: RA Capital Management, L.P. ("RA Capital") Peter Kolchinsky ("Dr. Kolchinsky") Rajeev Shah ("Mr. Shah") RA Capital Healthcare Fund, L.P. (the "Fund") The Reporting Persons expressly disclaim status as a "group" for purposes of this Schedule 13G.
(b)	Address or principal business office or, if none, residence: The address of the principal business office of each of the Reporting Persons is: c/o RA Capital Management, L.P., 200 Berkeley Street, 18th Floor, Boston MA 02116
(c)	Citizenship: RA Capital and the Fund are Delaware limited partnerships. Dr. Kolchinsky and Mr. Shah are United States citizens.
(d)	Title of class of securities: Class A Ordinary Shares, par value $0.0001 per share
(e)	CUSIP No.: G4444S107
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: Row 9 of each Reporting Person's cover page to this Schedule 13G sets forth the aggregate number of Class A ordinary shares of the Issuer beneficially owned by such Reporting Person and is incorporated by reference. The Fund directly holds 1,250,000 Class A ordinary shares of the Issuer. RA Capital Healthcare Fund GP, LLC is the general partner of the Fund. The general partner of RA Capital is RA Capital Management GP, LLC, of which Dr. Kolchinsky and Mr. Shah are the controlling persons. RA Capital serves as investment adviser for the Fund and may be deemed a beneficial owner, for purposes of Section 13(d) of the Act, of any securities of the Issuer held by the Fund. The Fund has delegated to RA Capital the sole power to vote and the sole power to dispose of all securities held in the Fund's portfolio, including the shares of the Issuer's Class A ordinary shares reported herein. Because the Fund has divested voting and investment power over the reported securities it holds and may not revoke that delegation on less than 61 days' notice, the Fund disclaims beneficial ownership of the securities it holds for purposes of Section 13(d) of the Act. As managers of RA Capital, Dr. Kolchinsky and Mr. Shah may be deemed beneficial owners, for purposes of Section 13(d) of the Act, of any securities of the Issuer beneficially owned by RA Capital. RA Capital, Dr. Kolchinsky, and Mr. Shah disclaim beneficial ownership of the securities reported in this Schedule 13G other than for the purpose of determining their obligations under Section 13(d) of the Act, and the filing of this Schedule 13G shall not be deemed an admission that either RA Capital, Dr. Kolchinsky, or Mr. Shah is the beneficial owner of such securities for any other purpose.
(b)	Percent of class: Row 11 of each Reporting Person's cover page to this Schedule 13G sets forth the percentages of Class A ordinary shares of the Issuer beneficially owned by such Reporting Person and is incorporated by reference. Such percentage is based upon 17,747,500 Class A ordinary shares outstanding as of January 26, 2026 following the consummation of the Issuer's initial public offering and the concurrent closing of a private placement of equity securities by the Issuer, as reported in the Issuer's Current Report on Form 8-K filed with the Securities and Exchange Commission (the "SEC") on January 30, 2026.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: Row 5 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person and is incorporated by reference.
	(ii) Shared power to vote or to direct the vote: Row 6 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person and is incorporated by reference.
	(iii) Sole power to dispose or to direct the disposition of: Row 7 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person and is incorporated by reference.
	(iv) Shared power to dispose or to direct the disposition of: Row 8 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person and is incorporated by reference.
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

RA Capital Management, L.P.

Signature:	/s/ Peter Kolchinsky
Name/Title:	By Peter Kolchinsky, Authorized Signatory
Date:	02/02/2026

Peter Kolchinsky

Signature:	/s/ Peter Kolchinsky
Name/Title:	Peter Kolchinsky
Date:	02/02/2026

Rajeev Shah

Signature:	/s/ Rajeev Shah
Name/Title:	Rajeev Shah
Date:	02/02/2026

RA Capital Healthcare Fund, L.P.

Signature:	/s/ Peter Kolchinsky
Name/Title:	By RA Capital Healthcare Fund GP, LLC, its General Partner, By Peter Kolchinsky, Manager
Date:	02/02/2026

Exhibit Information

Exhibit 99.1 Joint Filing Agreement

FAQ

What ownership stake in HLXC does RA Capital report on this Schedule 13G?

RA Capital Healthcare Fund, L.P. reports beneficial ownership of 1,250,000 Class A ordinary shares of Helix Acquisition Corp. III, representing 7.0% of the outstanding Class A shares based on 17,747,500 shares outstanding as of January 26, 2026.

Who are the reporting persons on the Helix Acquisition Corp. III (HLXC) Schedule 13G?

The reporting persons are RA Capital Management, L.P., RA Capital Healthcare Fund, L.P., and individuals Peter Kolchinsky and Rajeev Shah. RA Capital serves as investment adviser to the fund, and Kolchinsky and Shah manage RA Capital and may be deemed beneficial owners.

How is the 7.0% ownership in HLXC calculated in this Schedule 13G filing?

The 7.0% ownership is calculated from 1,250,000 Class A ordinary shares held by the fund, compared to 17,747,500 Class A ordinary shares outstanding as of January 26, 2026, following Helix Acquisition Corp. III’s initial public offering and concurrent private placement.

Does RA Capital seek control of Helix Acquisition Corp. III (HLXC) with this 7% stake?

The filing states the securities were not acquired and are not held for the purpose or effect of changing or influencing control of Helix Acquisition Corp. III. The position is reported on Schedule 13G, which is used for passive ownership under Section 13(d).

Who has voting and dispositive power over the HLXC shares reported by RA Capital?

RA Capital has been delegated the sole power to vote and dispose of all securities held by the fund, including the 1,250,000 Class A ordinary shares of Helix Acquisition Corp. III. The fund disclaims beneficial ownership because it has divested voting and investment power over these securities.

How do Peter Kolchinsky and Rajeev Shah relate to the HLXC shares in this Schedule 13G?

Peter Kolchinsky and Rajeev Shah are controlling persons of RA Capital’s general partner. They may be deemed beneficial owners of Helix Acquisition Corp. III shares for Section 13(d) purposes, but they expressly disclaim beneficial ownership other than for meeting reporting obligations.